Incision device capable of automatic assembly and a method of assembly

ABSTRACT

An apparatus for implementing a skin incision has a torsion spring and a method of assembling the apparatus. The apparatus has a housing having a pair of housing sections, each of the housing section having a base and a plurality of walls. The housing defines an inner space and an exterior. A pivot arm is pivotally mounted to a base of a housing section. The pivot arm is guided between a first position and a second position by a follower in a cam carried by the housing. A torsion spring carried by a spring post is coupled to the arm to exert a spring force on the arm in the first position. The housing has an indentation with a raised level and a lower groove on the base for receiving a portion of the spring post. The opening through the base extends from the lower groove. The spring post has a cylindrical base portion adapted to be received by the indentation in the base and a detent portion. The detent portion has a circular segment detent portion and a turn element accessible from the exterior of the housing. The circular segment detent portion is adapted to engage the raised level of the indentation in the install position and be retained in the lower groove in the loaded position. A trigger mechanism is received in the housing and acts with the pivot arm when activated whereby the arm moves from the first position to the second position due to the spring energy.

This is a divisional of application Ser. No. 08/718,774, filed Sep. 24,1996 now U.S. Pat. No. 5,772,677.

FIELD OF THE INVENTION

The invention relates to an apparatus for providing a skin incision inorder to cause bleeding and more particularly to a disposable devicewhich provides a precisely controlled incision in the skin of thepatient, can be automatically assembly, and can have its spring woundduring final assembly.

BACKGROUND OF THE INVENTION

Disposable skin incision devices have been produced and marketed formany years. In a majority of these skin incision devices, a trigger ispushed which causes a blade to project out of a slot in the housing andthen to retract back into the housing. The skin incision device has aspring or a flexural member which upon triggering produces the force toproject the blade out of the housing into the skin and retract theblade. A skin incision device having a spring is described in U.S. Pat.No. 4,643,189 entitled "Apparatus for Implementing A Standardized SkinIncision" which issued to Mintz on Feb. 17, 1987, and is incorporatedherein by reference.

In skin incision devices which use a spring, the spring must betensioned or cocked in order to achieve the desired result. Inassembling the skin incision device, the spring must be tensioned andthen held in tension while the skin incision device is being assembled.

It would be desirable to assemble the spring in the skin incision devicein a non-tension position and then tension the spring at a later time.

SUMMARY OF THE INVENTION

This present invention is directed to an apparatus for implementing askin incision and a method of assembling the apparatus. The apparatushas a housing having a pair of housing sections. Each of the housingsections has a base and a plurality of walls. The housing defines aninner space and an exterior. A pivot arm is pivotally mounted to a baseof a housing section. The pivot arm is guided between a first positionand a second position by a follower in a cam carried by the housing. Atorsion spring carried by a spring post is coupled to the arm to exert aspring force on the arm in the first position. The housing has anindentation with a raised level and a lower groove on the base forreceiving a portion of the spring post. The opening through the baseextends from the lower groove. The spring post has a cylindrical baseportion adapted to be received by the indentation in the base and adetent portion. The detent portion has a circular segment detent portionand a turn element accessible from the exterior of the housing. Thecircular segment detent portion is adapted to engage the raised level ofthe indentation in the install position and be retained in the lowergroove in the loaded position. A trigger mechanism is received in thehousing and acts with the pivot arm when activated whereby the arm movesfrom the first position to the second position due to the spring energy.

One object, feature, and advantage resides in the housing having anindentation with a raised level and a lower groove on the base forreceiving a portion of the spring post, and the circular segment detentportion of the spring post adapted to engage the raised level of theindentation in the install position and be retained in the lower groovein the loaded position. Another object, feature, and advantage residesin the torsion spring having a circular core and a pair of legs, thecircular core of the torsion spring encircling the spring post, and thespring post having a slot for receiving one of the legs of the spring.Further objects, features, and advantages of the present invention willbecome more apparent to those skilled in the art as the nature of theinvention is better understood from the accompanying drawings anddetailed descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there is shown in thedrawings a form which is presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIG. 1A is a rear view of a skin incision apparatus, according to theinvention

FIG. 1B is a front view of the skin incision apparatus. Selected partsare shown in hidden line.

FIG. 2 is a bottom plan view of the apparatus;

FIG. 3A is an inside view of a first housing section of the apparatus;

FIG. 3B is a sectional view taken along the line 3B--3B in FIG. 3;

FIG. 3C is a sectional view taken along the line 3C--3C in FIG. 3A;

FIG. 4A is an inside view of a second housing section of the apparatus;

FIG. 4B is a section view taken along the line 4B--4B in FIG. 4A;

FIG. 4C is a sectional view taken along the line 4C--4C in FIG. 4A;

FIG. 5A is a front view of a pivot arm and a cutting edge employed inthis invention;

FIG. 5B is a rear view of the pivot arm and the cutting edge;

FIG. 6A is a front view of a trigger mechanism or plunger employed inthis invention;

FIG. 6B is a bottom view of the trigger mechanism;

FIG. 7 is an enlarged front view of a torsion spring;

FIG. 8A is a side view of a spring post;

FIG. 8B is a front view of the spring post;

FIG. 8C is a rear view of the spring post;

FIG. 9A is an inside view of a first housing section with the pivot arm,and the spring and the spring post installed in an installationposition;

FIG. 9B is a section view taken along the line 9B--9B in FIG. 9A;

FIG. 9C is a sectional view taken along the line 9C--9C in FIG. 9A;

FIG. 10A is a front view of the apparatus with a portion of the base ofthe front housing section broken away to show the interior;

FIG. 10B is a sectional view taken along the line 10B--10B in FIG. 10A;and

FIG. 11 is a top view of a turntable for automatically assembly withvarious components shown broken away or in hidden line.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now the drawings, wherein like numerals indicate likeelements, there is illustrated in FIG. 1 a rear view of an apparatus forskin incision which has been identified by the numeral 20.

The skin incision apparatus 20 has a housing 22 having a pair of housingsections 24 and 26, only one section, the rear section 24, seen inFIG. 1. A trigger mechanisms 28 of and for activating the skin incisionapparatus 20 projects through an opening 30, as best seen in FIGS. 3Aand 4A, formed between the two section 24 and 26 of the housing 22. Thetrigger mechanism 28 is also referred to as a plunger. The rear section24 of the housing 22 has a hole 32 through which a portion of a springpost 34 projects.

The skin incision apparatus 20 has a keeper or safety device 38 whichcan be removed from a safety position surrounding a portion of thetrigger mechanism 28 to prevent inadvertent operation. The keeper 38 isshown removed in FIG. 1A.

The front housing section 26 with the surface configuration not shownand selected components of the skin incision apparatus 20 are shown inhidden line is seen in FIG. 1A. The skin incision apparatus 20 has, inaddition to the housing 22, the trigger mechanism 28, and the springpost 34, not seen in FIG. 1A, a pivot arm 40 which carries a blade 42,and a torsion spring 44. The pivot arm 40, the spring post 34, and thetorsion spring 44 are located in an inner space 46 defined by thehousing sections 24 and 26. When the trigger mechanism 28 ispushed/pressed inwardly, to the left in FIG. 1A, the trigger mechanism28 releases the pivot arm 40 and the torsion spring 44 rotates the pivotarm 40 such that the blade 42 passes through a slot 48, as seen FIG. 2,and retracts back into the housing 22.

In order to gain some insight into the dimensions of an actual unit, atypical unit has a height A of approximately 1.19 inches with a bottomlength B of 1.125 inches; the top length being slightly less than thebottom length. The unit has width C, as seen in FIG. 2, of about 0.4375inches.

Each of the housing sections 24 and 26 has a base 50 and four walls 52,54, 56, and 58 projecting from the base 50. The bottom wall 54 of eachof the housing sections 24 and 26 is shown in FIG. 2. The bottom wall54f and 54r are joined together to define the slot 48, through which theblade 42 passes during operation or when activated.

The base 50r and the four walls 52r, 54r, 56r and 58r projecting fromthe base 50r of the rear housing section 24 are seen in FIG. 3. The fourwalls 52r, 54r, 56r, and 58r and base 50r define a portion of the innerspace 46. Located generally where two walls join to form a corner is anopening 60.

Referring to FIGS. 3A and 3B, the rear housing section 24 has a raisedportion or bulkhead 62 projecting from the base 50r. The raised portion62 defines a convoluted cam channel 64. Located between the convolutedcam channel 64 and the slot 48, defined by the bottom wall 54, is acircular boss 66 which surrounds an extending rod 68. The post 68, asexplained below, acts as a pivot point for the pivot arm 40 containingthe blade 42.

Referring to FIG. 3A and 3A, the rear housing section 24 has a secondcircular boss 70 defining an indentation 72 for receiving a portion ofthe spring post 34. The indentation 72 has a bi-level surface 74 at thebase 50r; the bi-level surface includes a raised level 76 on either sideof a lower groove 78. In the center of the lower groove 78 is the hole32 seen in FIG. 1.

Still referring to FIG. 3A, the rear housing section 24 has a post 80that projects upwards. The post 80 engages the base 50f of the fronthousing section 26 as described below. The base 50r, in addition, formsa ridge 82 upon which the trigger mechanism 28 slides. The top wall 58rof the housing section 24 has a projecting member 84, a stop member,which projects into the inner space 46 for limiting movement of thetrigger mechanism 28.

The base 50f and the four walls 52f, 54f, 56f, and 58f projecting fromthe base 50r of the front housing sections 26 are seen in FIG. 4A. Thefour walls 52f, 54f, 56f, and 58f and base 50f define a portion of theinner space 46. Located generally in the locations where two walls jointo form a corner are pins 86, as seen in FIGS. 4A, 4B, and 4C, which arereceived by the openings 60 in the rear housing section 24.

Referring to FIG. 4A and 4B, the front housing section 26 has asemi-circular boss 88 for holding the pivot arm 40 containing the blade50 in position, as explained below.

The top wall 58f of the housing section 26 has a projecting member 84, astop member, which projects into the inner space 46 for limitingmovement of the trigger mechanisms 28. The front housing section 26 hasa circular boss 90 defining an indentation 92 for receiving a portion ofthe spring post 34 as seen in FIGS. 4A and 4C. The indentation 92 has araised protrusion 94 at the base 50f.

Still referring to FIG. 4A, the front housing section 26 has a dimple 96for receiving the tip of the post 80 that projects from the rear housingsection 24. The base 50f, in addition, forms a ridge 82 upon which thetrigger mechanism 28 slides.

Referring to FIG. 5A, the pivot arm 40 has a shoulder 98 defined by twodifferent level surfaces. The shoulder 98 is engaged by the torsionspring 44, as defined below. A recess 100 is formed for part of theshoulder 98, and is shown in hidden line. The blade 42, a triangularblade with a cutting edge 102 and a sharpened apex 104 is coupled to thepivot arm 40. The blade 42 may be secured to the pivot arm 40 by anyconventional means and is scalpel-like in appearance and function.Located on the top of the pivot arm 40 is a keeper section 106 whichacts with the end of the trigger mechanism 28 to retain the pivot arm 40in a first position prior to actuation of the skin incision apparatus20.

Referring to FIG. 5B, the pivot arm 40 has an extended cam follower rod108 which extends into the convoluted cam channel 64. The convoluted camsurface of the cam channel 64 controls the movements of the pivot arm 40and, therefore, of the cutting edge 102 of the blade 42 when the skinincision apparatus 20 is activated. A raised boss 110 projects from thepivot arm 40 to define an elongated aperture 114.

The trigger mechanism 28 has a sloping front end 116 as seen in FIG. 6Awhich acts with the keeper section 106 of the pivot arm 40 duringoperation. The trigger mechanism 28 also contains a top channel 118which abuts against the stop member 84 of the housing 22. Referring toFIG. 6B, the trigger mechanism 28, also referred to as a plunger member,has a hallow section 120 through which the keeper section 106 of thepivot arm 40 passes as it moves, as explained below.

FIG. 7 is an enlarged side view of the torsion spring 44. The spring 44has a core 122 and a pair of legs 124 and 126. The first leg 124projects inwardly and bisects the core 122. The second leg 126 extendsgenerally out at a tangent from the core 122. The second leg 126 has abend or jog 128, which facilitates assembly as discussed below.

Referring to FIGS. 8A, 8B, and 8C, the spring post 34 is adapted tocarry the spring 44. The spring post 134 generally has a cylindricalshape and includes a cylindrical base portion 130, a raised detentportion 132, and a reduced diameter cylindrical portion 134. The raiseddetent portion 132 projects from the cylindrical base portion 130 to afirst end 136. The raised detent portion 132 has a circular segmentdetent portion 138 projecting from the cylindrical base portion 130. Acylindrical guide portion 140 projects from the detent portion 138. Thecylindrical guide portion 140 has an outside diameter no greater thanthe width of the circular segment detent portion 138 and is received bythe hole 32 in the rear housing section 24, as seen in FIGS. 1 and 3. Aturn element 142 for setting or loading the spring 34, as describedbelow, projects from the end of the cylindrical guide portion 140. Theturn element 142, similar to the circular segment detent portion 138,has a pair of parallel edges 144 spaced by circular arc edges, in apreferred embodiment, as best seen in FIG. 8B.

The reduced diameter cylindrical portion 134 of the spring post 34extends from the base portion 130 to a second end 146. A slot 148 in thereduced diameter cylindrical portion 134 extends from the second end 146to approximately the cylindrical base portion 130. The intersection ofthe base portion 130 with the reduced diameter cylindrical portion 134defines a shoulder 150.

Referring to FIGS. 9A and 9B, the skin incision apparatus 20 isassembled by placing the pivot arm 40 in the rear housing section 24such that the extended cam follower rod 108 is received by theconvoluted cam channel 64 and the elongated aperture 114 defined by theraised boss 110, as best seen in FIGS. 9B and 5B, receives the extendingrod 68 of the rear housing section 24. The pivot arm 40 is positioned inthe first position, the actuation position, with the keeper section 106to the left in FIG. 9A.

Prior to installing the torsion spring 44 and the spring post 34, theleg 124 is received by the slot 148 in the reduced diameter cylindricalportion 134 of the spring post 34, such that the core 122 of the spring44 encircles the reduced diameter portion 134 of the post 34. The spring44 is located on the shoulder 150 defined by the base portion 130 andthe reduced diameter cylindrical portion 134. Referring to FIG. 9A and9C, the spring post 34 is positioned on the rear housing section 24 sothat the raised detent portion 132 of the spring post 34 is received bythe second circular boss 70 on the base 50 of the rear housing section24. The circular segment detent portion 138 is positioned so that itdoes not align with the lower groove 78 of the bi-level surface 74, asbest seen in FIG. 9C. The turn element 142, in a preferred embodiment,is located in the hole 32 in the base 50 of the rear housing section 26.The second leg 128 is received by the shoulder 98 in the pivot arm 40.The bend or jog 128 in the leg 126 of the spring 44 reduces the chanceof interference with the front housing section 26 during assembly.

The trigger mechanism 28 is installed on the ridge 82. The sloping frontend 116 is positioned to engage the keeper section 106 of the pivot arm40. The top channel 118 is positioned to receive the stop member 84. Thekeeper or safety device 38 can be installed on the trigger mechanism 28at this time.

Referring to FIGS. 10A and 10B, the front housing section 26, ispositioned on top of the rear housing section 24 such that the pins 86,as seen in FIG. 4A, are received by the openings 60, as seen in FIG 9A,in the rear housing section 24. The semi-circular boss 88 of the fronthousing section 26 is positioned above the pivot arm 40, in proximity towhere the blade 42 is mounted to the pivot arm 40. The reduced diametercylindrical portion 134 of the spring post 34 is received in theindentation 92 defined by the circular boss 90 of the front housingsection 26. The slot 148 is not aligned with the raised protrusion 94 inthe circular boss 90, at least initially. The position of the slot 148is shown in FIG. 9A.

With the circular segment detent portion 138 of the spring post 34 notlocated in the lower groove 78 of the bi-level surface 74 of the secondcircular boss 70 of the rear housing section 24 and the raisedprotrusion 94 on the front housing section 26 not received by the slot148 of the spring post 34, the walls 52, 54, 56, and 58 of the twohousing sections 24 and 26 do not engage completely, specifically walls54 and 56 which are close to the spring post 34.

With the two housing sections 24 and 26 held together, the turn element142 is rotated using a tool 154, as seen in FIG. 11, which complementsthe shape of the turn element. The turn element 142 is turned clockwiseas seen in FIGS. 9 and 10A, and counterclockwise as seen in FIG. 1. Therotation of the turn element 142 rotates the spring post 34, thereinmoving the first leg 124 of the spring 44 which is received by the slot148 in the reduced diameter cylindrical portion 134 of the spring post34. In the assembly, the first leg 124 is the movable end or leg totension the spring 44. The second leg 126, which is received by theshoulder 98 of the pivot arm 40, is the stationary end. The turn element142 is rotated until the circular segment detent portion 138 of thespring post 34 aligns with the lower groove 78 of the bi-level surface74 of the second circular boss 70 of the rear housing section 24 and theraised protrusion 94 on the front housing section 26 is received by theslot 148 of the spring post 34. With the alignment, the walls 52, 54,56, and 58 of the two housing sections 24 and 26 do mesh, as shown inFIG. 10B.

With the spring 44 wound and the housing 22 closed, the skin incisionapparatus 20 is ready to operate. The keeper 38 is removed from thetrigger mechanism 28. The trigger mechanism 28 is pushed inward, to theleft in FIG. 1A. As the trigger mechanism 28 is pushed, the slopingfront end 116 pushes the pivot arm 40 towards the left until the pivotarm 40 clears the sloping front end 116 of the trigger mechanism 28.With the pivot arm 40 cleared, the spring 44 pivots the entire pivot arm40. As the spring rotates the pivot arm 40, the second leg 126 rotatesand is the movable end, and the first leg 124, the stationary end, isheld by the spring post 34 which is held by the bi-level surface 74 ofthe rear housing section 24 and the raised protrusion 94 of the fronthousing section 26.

The pivot arm 40 moves with the extended cam follower rod 108 followingthe convoluted cam channel 64. The shape of the convoluted cam channel64 converts the generally arcuate motion of the pivot arm 40 into alinear portion for a segment of the motion of the blade 42. Theoperation is such that the apex 104 of the blade 42 punctures the skinand thereafter the cutting edge 102 incises the skin. At the end of thetravel, the blade 42, including the apex 104, is withdrawn from the skinback into the housing 22.

It is recognized that assembly could occur without assistance of humans,such as on a turntable 156 as shown in FIG. 11. The turntable 156 has aplurality of orifices 158 which are of a shape similar to that of therear housing section 24, with an additional notch for the placing of thekeeper 38. In a preferred embodiment, the turntable 156 has eight (8)orifices 158. The turntable 158 has a plate 160, shown in hidden line,which is generally annular and underlies all of the orifices 158, exceptone as explained below, for retaining the skin incision apparatus 20.

The rear housing section 24 slides into an orifice 158 from a ramp 162at station I. The turntable is rotated, by a motor mechanism 164 shownin hidden line, to the next position, or station. While the next rearhousing section 24 is being loaded into the next orifice 158, the pivotarm 40 is loaded by a robotic arm, not shown, at the next station(station II) into the rear housing section 24. In the next station(station III), after rotation of the turntable 156, the triggermechanism 28 and keeper 38 are loaded as a unit. The keeper 38 is loadedon the trigger mechanism 28 prior to installation in station III.

Prior to installing the torsion spring 44 and the spring post 34, theleg 124 of the spring 44 is received by the slot 148 in the reduceddiameter cylindrical portion 134 of the spring post 34, such that thecore 122 of the spring 44 encircles the reduced diameter portion 134 ofthe post 34. The spring 44 is located on the shoulder 150 defined by thebase portion 130 and the reduced diameter cylindrical portion 134. Thespring post 34 is positioned on the rear housing section 24 (in stationIV) so that the raised detent portion 132 of the spring post 34 isreceived by the second circular boss 70 on the base 50 of the rearhousing section 26, similar to that described above with reference FIGS.9A and 9C. The second leg 128 is received by the shoulder 98 of thepivot arm 40.

With all the parts located on the rear housing section 24, the fronthousing section 26 is positioned on the rear housing section 24 instation V. The pins 86, as seen in FIG. 4A of the front housing section26 are received by the openings 60 in the rear housing section 24. Asindicated above, the walls 52, 54, 56, and 58 of the two housingsections 24 and 26 do not engage completely. The turntable rotatesmoving the housing sections 24 and 26 under a spring loaded plate 166,which urges the front housing section 26 into engagement with the rearhousing section 24. The spring loaded plate 166 overlies stations VI andVII. In a preferred embodiment, no operation occurs at station VI.

At the next station (Station VII), a tool 154, shown exploded away inFIG. 11, moves into engagement with the turn element 142 of the springpost 34, as seen in FIG. 1 and (C, rotates the spring post 34, thereinmoving the first leg 124 of the spring 44 which is received by the slot148 in the reduced diameter cylindrical position 134 of the spring post34. The turn element 142 is rotated until the circular segment detentportion 138 of the spring post 34 aligns with the lower groove 78 of thebi-level surface 74. The spring loaded plate 166 urges the front housingsection into engagement with the rear housing section.

The turntable 156 rotates to a final station (station VIII) where theunderlying plate 160 is not located. The skin incision apparatus 20drops to a chute 168 or a conveyor, to move to a packaging section, notshown. It is recognized that the turntable 156 could have fewer or morestations. It is also recognized that multiple parts could be loaded atone station or a plurality of stations could have the same operationbeing performed and the turntable turns a plurality of orifices at onetime. In addition, it is recognized that there are other methods ofassembling the skin incision apparatus 20 automatically.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes therefore and,accordingly, references should be made to appended claims, rather thanto the foregoing specification, as indicating the scope of theinvention.

We claim:
 1. An apparatus for implementing a skin incision comprising:ahousing having an inner space and an exterior, said housing havinglocated on a first surface an elongated slot, the elongated slot beingadapted to placed against a patient's skin and housing further having asecond surface having located therein an aperture; a movable armpivotally mounted to the housing for movement between a first positionand a second position; spring bias means coupled to the arm to exert aspring force on the arm in the first position; and, spring carryingmeans being carried by the housing; wherein said spring carrying meansare accessible from the exterior of the housing through said aperture tobe moved from an install position to a loaded position.
 2. An apparatusfor implementing a skin incision as in claim 1 further comprisingactivatable releasing means coupled to the housing and co-acting withthe movable arm when activated whereby the arm moves from the firstposition to the second position due to the spring bias.
 3. An apparatusfor implementing a skin incision as in claim 1 further comprising:cammeans carried by the housing; and the movable arm having a cam co-actingmeans adapted to interact with the cam means for guiding the movementbetween the first position and the second position.
 4. An apparatus forimplementing a skin incision as in claim 3 wherein the housing has aplurality of housing sections, at least one of the housing sections hasa base including said aperture, and the spring carrying means is aspring post located within the inner space defined by the housing andhaving a turn element projecting through the aperture in the base foraccessing from the exterior of the housing.
 5. An apparatus forimplementing a skin incision as in claim 4 wherein the housing has anindentation on the base for receiving a portion of the spring post, theindentation having a raised level and a lower groove, the aperturethrough the base extending from the lower groove, the spring post havinga cylindrical base portion adapted to be received by the indentation inthe base and a detent portion, the detent portion having a circularsegment detent portion and the turn element, the circular segment detentportion adapted to engage the raised level of the indentation in theinstall position and be retained in the lower groove in the loadedposition.
 6. An apparatus for implementing a skin incision as in claim 5wherein the spring bias means is a torsion spring having a circular coreand a pair of legs, the circular core of the torsion spring encirclingthe spring post, and the spring post having a slot for receiving one ofthe legs of the spring.
 7. An apparatus for implementing a skin incisioncomprising:a housing comprising a pair of housing sections and having aninner space and an exterior, said housing having an elongated slot in afirst surface, said elongated slot adapted to be placed against apatient's skin, each of the housing sections comprising a base and aplurality of walls; cam means carried by the base of one of the housingsections; a pivot arm pivotally mounted to the base of one of thehousing sections within the inner space and having a cam coacting meansadapted to interact with the cam means, the cam means guiding themovement of the pivot arm between a first position and a secondposition; spring bias means coupled to the arm to exert a spring forceon the arm in the first position; an aperture in one of said bases;spring carrying means for carrying the spring bias means, the springcarrying means carried with in the inner space defined by the housingand being adapted to be accessible from the exterior of the housingthrough the aperture to be moved from an install position to a loadedposition; and activatable releasing means coupled to the housing andcoacting with the pivot arm when activated whereby the arm moves fromthe first position to the second position due to the spring bias.
 8. Anapparatus for implementing a skin incision as in claim 7 wherein saidspring carrying means is a spring post located within the inner spacedefined by the housing and has a turn element projecting through theaperture in the base for accessing from the exterior of the housing. 9.An apparatus for implementing a skin incision as in claim 8 wherein thecam means formed integral with the base of one of the housing sectionshas a given arcuate surface having a series of convolutions; and thepivot arm guided by the cam whereby the arm can pivot along a pathtraversing the slot, and the pivot arm carrying cutting edge meanscoupled to the arm and positioned within the housing in the firstposition of the arm and adapted to extend and retract from the slot whenthe arm is moving to the second position.
 10. An apparatus forimplementing a skin incision as in claim 9 wherein the housing has anindentation on the base for receiving a portion of the spring post, theindentation having a raised level and a lower groove, the aperturethrough the base extending from the lower groove, the spring post havinga cylindrical base portion adapted to be received by the indentation inthe base and a detent portion, the detent portion having a circularsegment detent portion and the turn element, the circular segment detentportion adapted to engage the raised level of the indentation in theinstall position and be retained in the lower groove in the loadedposition.
 11. An apparatus for implementing a skin incision as in claim10 wherein the spring bias means is a torsion spring having a circularcore and a pair of legs, the circular core of the torsion springencircling the spring post, and the spring post having a slot forreceiving one of the legs of the spring.
 12. An apparatus forimplementing a skin incision as in claim 11 wherein the pivot arm has ashoulder for receiving one of the legs of the torsion spring.
 13. A skinincision apparatus comprising:a housing having an inner space and anexterior, said housing having located on a first surface an elongatedslot, the elongated slot being adapted to place against a patient'sskin, said housing including at least first and second housing sections,each housing section having a base, said first housing section furtherincluding a cam and a pivot point carried by the base; a moveable armincluding a pin and an opening, wherein said pin is adapted to bereceived by said cam, and said opening is adapted to receive said pivotpoint; a spring carrying means adapted to be coupled to said firsthousing section; a spring bias means coupled to said spring carryingmeans; and, an aperture in said base of one of said first and secondhousing sections; wherein said second housing section is adapted to becoupled to said first housing section such that the moveable arm, thespring bias means and the spring carrying means are interposed betweenthe bases of the housing sections, a portion of the spring carryingmeans contained within the housing is externally accessible through saidaperture, and said portion of the spring carrying means which isexternally accessible through said aperture is adapted to move thespring bias means from an installation position to a loaded positionafter the second housing section has been coupled to said first housingsection.
 14. A skin incision apparatus, comprising:a first housingsection having a first surface having located therein at least a portionof an elongated slot, said elongated slot adapted to be placed against apatient's skin; said first housing section including a base, said baseincluding a cam, a pivot point and an aperture; a pivot arm including akeeper section and adapted to be carried by said first housing section;a trigger mechanism adapted to be carried by the first housing section,said trigger mechanism adapted to engage said keeper section of saidpivot arm; a spring post adapted to carry a torsion spring in the firsthousing section such that a turn element of the spring post extendsthrough said aperture in the base of the first housing section; and, asecond housing section having a base and adapted to be coupled to saidfirst housing section such that the pivot arm, the spring post, and thespring are interposed between the bases of said first and second housingsections; wherein the spring post is further adapted to be rotated usingsaid turn element to move the spring from the first position to a secondposition.